Alkeria NECTA Series - Line Start Trigger; Acquisition Start Trigger; Frame Start Trigger

6. Trigger 71
External Trigger is generated on the detection of an input event. The trigger module can be activated
either by the rising edge or by the high level; the input logic can also be reversed in order to
detect the falling edge or the low level.
Software Trigger is generated through the SoftwareTrigger software method.
PLL Trigger is generated by the tick of the frequency multiplier module (see Section 4.4.2).
Encoder Trigger is generated whenever the encoder position counter increases by a programmable
number of steps (set through the EncoderInterval property).
EncoderOnce Trigger is generated only the rst time the encoder position counter reaches the value of
EncoderInterval property.
Table 6.1:
Trigger sources
6.2 ACQUISITION START TRIGGER
The acquisition-start trigger (AcquisitionStartTrigger) event enables the acquisition of a given
number of frames, called a burst. When the module is enabled
1
, the camera waits for a start acquisition
trigger before starting capturing a burst.
The number of frames in a burst is set by the AcquisitionBurstLength property; when the burst
is complete, the camera waits for a new start acquisition trigger, that will trigger the acquisition of the
next burst.
The sources available for this module are External, Software, Encoder and EncoderOnce. When this
module is disabled
2
, the acquisition is always active.
6.3 FRAME START TRIGGER
The frame-start trigger (FrameStartTrigger) event enables the acquisition of a frame, i.e. the expo-
sure of a given number of lines. When the module is enabled
3
, the camera waits for a frame start trigger
before capturing lines.
The number of lines acquired after the frame start trigger is set by the ImageSizeY property, as de-
scribed in Section 8.3; when the required the number of lines has been acquired, the camera waits for a
new frame start trigger, that triggers the acquisition of the next frame.
The sources available for this module are External, Software, PLL and Encoder. When the module is dis-
abled
4
, the frame starts on the rst line’s trigger.
6.4 LINE START TRIGGER
The line-start trigger (LineStartTrigger) is the event that triggers the exposure of a line. The sources
available for this module are External, Software, PLL and Encoder.
1
AcquisitionStartTrigger.Enabled = true
2
AcquisitionStartTrigger.Enabled = false
3
FrameStartTrigger.Enabled = true
4
FrameStartTrigger.Enabled = false